The visible light mediated metal-free approach has been developed for C–H arylation and borylation employing anilines as starting material. A series of meso-aryl corroles (A3 and A2B type) were synthesized and their catalytic potential was tested in blue light and sunlight. The method includes substituted anilines as source of expensive aryl diazonium salts and utilizes only 0.5 to 1 mol% of corrole catalyst at room temperature. Corrole catalyst worked efficiently under the blue light/sunlight to produce heterobiaryls and aryl boronic esters in decent to good yields (15–80 %). Mechanistic insight was obtained from TD-DFT studies, which suggested single electron transfer (SET) from the singlet state of corrole catalyst to the aryl diazonium salt. The paper demonstrates corrole based photo-redox catalysis as a mild, green and eco-sustainable alternative for the C–H arylation reactions.
Harappan horn-headed figures are reported from eleven early Harappan and Harappan sites in Sind and Punjab provinces, Gomal valley, Haryana, Rajasthan and Gujarat, and one Neolithic site in Kashmir. Many scholars have interpreted the figures as the representation of pasupati, “Lord of Beasts” and by others as part of a hunting cult. Likewise, the gender of the figure has been a subject of discussion. Males of the simple living communities in India use identical horn-headed headgear. The discovery of a more or less similar horn-headed painted ceramic sherd from the Harappan site at Bhagatrav in Gujarat is significant. It suggests that horn-headed headgear was part of the lifeways of the entire Harappans in both time and space. Till now, what had been reported was in the form of incised seals, tablets, relief, and pre-fire painting on the outer side of the pots. The figure from Bhagatrav would appear to be that of a double-horned head and is unique for its representation on the inner side of a bichrome dish.